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	Director, Operational Test & Evaluation
FY97 Annual Report

ENHANCED POSITION LOCATION REPORTING SYSTEM (EPLRS)

	Army ACAT II Program 4,417 systems (Radio) 25 (NCS) Total program cost (TY$) $929.8M Average unit cost (TY$) Radio $27.9K NCS $800K Full-rate Production 2QFY97 Prime Contractor Hughes Aircraft Company

SYSTEM DESCRIPTION & CONTRIBUTION TO JOINT VISION 2010

For successful implementation of the Joint Vision 2010 operational concepts of dominant maneuver, precision engagement, focused logistics, and full-dimensional protection, enhanced command and control is essential. In anticipation of significant operational advantages, the Army recognizes that enhanced tactical communications is the first step. For the near future, the Enhanced Position Location Reporting System (EPLRS) is to play a vital role in the Army's modernization efforts to achieve a digitized battlefield.

The EPLRS is a secure, electronic warfare-resistant tactical transmission system supporting the Army Tactical Command and Control System (ATCCS) and the Army Battle Command System. EPLRS provides position location and navigation (POSNAV) information that is more readily known as situational awareness information. EPLRS also is the proposed communications backbone of the Tactical Internet supporting the Army's Force XXI experiment.

Major components of the EPLRS system are the EPLRS Net Control Station (NCS) and the EPLRS radio set. The EPLRS NCS establishes and controls the network of individual radio sets. Two networks provide communications within the EPLRS Time Division Multiple Access architecture. They are the control net and the communications net. Communications within the control net are brief messages requesting latest position, bearing to a location, or time of day. The communications net sends messages composed of multiple transmission units or packets via needlines where these messages are transmitted directly between the sender and receivers using EPLRS radio relays.

The final Low Rate Initial Production option for EPLRS was awarded in May 1993. The net control station has been downsized from a shelter on a 5-ton truck to a rigid-wall shelter on a High Mobility Multiwheeled Vehicle. The EPLRS radio also has been redesigned twice with the EPLRS System Improvement Program (SIP) radio incorporating the most recent changes.

Another redesign of the radio is planned after the Milestone III decision through a Value Engineering Change Proposal (VECP). The VECP radio is to reduce the number of circuit card assemblies from 11 to 3 and increase the transmission rate of the radio to 100,000 bps.

The EPLRS completed its second IOT&E in December 1996. The IOT&E II was to determine the operational effectiveness and operational suitability of the downsized EPLRS NCS and the EPLRS radio. The IOT&E II had two phases.

Phase 1, conducted at Electronic Proving Ground (EPG), Fort Huachuca, AZ, included two downsized NCSs, 15 SIP radios, and 103 Very High Speed Integrated Circuit (VHSIC) radios. This phase integrated DT and OT to address the critical operational issues. Six SIP radios provided data to evaluate horizontal POSNAV accuracy for ground EPLRS radios. The absence of airborne platforms prevented evaluation of vertical accuracy. The remaining radios passed scripted messages to support evaluating message completion. Two heliborne jammers replicated a moderate- to high-electronic warfare environment.

Phase 2 of the EPLRS IOT&E was a three-day training exercise at Fort Hood, TX. Phase 2 testing was in conjunction with the Force XXI brigade field training exercise and included approximately 300 VHSIC radios in a network controlled by one downsized NCS. Phase 2 tested POSNAV accuracy in an extended network.

The data from the IOT&E II and the previous operational tests for EPLRS were sufficient to conclude that the current version of EPLRS, the downsized NCS and the SIP radio, effectively disseminated short messages, such as those used in the air defense application. The data were not sufficient to demonstrate effectiveness for long messages. Approximately 15 percent of the message traffic in recent ATCCS tests were messages longer than those used to stimulate EPLRS. Since message completion rates decrease as the size of messages increase, it is important to test communications with appropriate messages. Message completion rates for relatively short messages were high, and speed of service consistently met the established criteria. While the jamming environment did reduce the completion rate, the system performed well. Test limitations precluded a determination of effectiveness for other applications. Not testing EPLRS communications on the move significantly limited the ability to determine the effectiveness of EPLRS for other applications.

The IOT&E II provided sufficient data to determine that EPLRS is operationally suitable although data were not sufficient to completely assess training. While the test team was well trained on earlier EPLRS equipment, neither new equipment nor institutional training was administered to all members of the test team. We recommend that the new equipment training program be administered to the first unit equipped and an assessment of the training program be conducted at that time.

The VECP radio is a new design that must be operationally tested before it is fielded. The testing of the VECP should include the higher data rates, new operating modes, and longer message lengths that were not tested in the IOT&E II.